52telecaster

I have tried this technique twice now and had some success. For bikes that don't have enough space at the chainstays I use a piece of pipe with the o.d. of 2". I put a hub in the bikes dropouts and pound the pipe into the chain stays behind the bottom bracket. It doesn't yield huge room but it gives you enough for 42s and in both cases the rear dropout spacing was essentially the same after. I use a 2 pound sledge and go slow but it does seem to work. I did it first on an 88-89 letour and just did it on an old motobecane grand touring. This may be horrifying by some standards but it seems to work for me.

Motobecane

ThermionicScott 

I've seen pictures of people using vise-grips with no padding (!) to indent chainstays, so tapping dimples with a hammer sounds downright humane.

Speaking of "making room", I think your camera would have an easier time focusing on the chainstays if you backed up a little.

52telecaster

I should take better pics

52telecaster

the hammer taps the pipe in between the stays

52telecaster

lonesomesteve

Your technique looks like it works more or less, but I'd be a little worried about spreading out the angles where the chainstays meet the bottom bracket shell. But then, maybe that's a good thing since it gives you more clearance, which after all is what you're after.

I generally use a large set of vice grips to gently squeeze the dimples. I protect the out side of the chainstay with piece of 3/4'' copper tubing cut in half lengthwise, and use a small socket wrench on the inside that roughly has the contour/size of the dimple I'm trying to make.

I know for sure that however you do it, you still need to check alignment and spacing after you're done, even if you have a rear dummy hub installed while doing the dimpling.

Andy_K 

The last picture is helpful. I was imagining the 2" pipe going in end first, and it seemed horrible. I guess with that, you have three forces resisting the pipe -- the inside curvature of the stays, the linear alignment of the stays, and the strength of the chainstay bridge. Which one is going to give first? It sounds like you've experimentally determined that to be the curvature of the stays, though I'd be curious if you've measured the rear dropout spacing while the pipe is hammered in place. I recently read someone suggesting a toe strap wrapped around the chainstays at the bridge to support the braze while cold setting rear spacing. I'm not convinced a toe strap has more strength than the braze, but maybe if it's an old Raleigh....

Since I think @gugie is traveling today, I'll do some work as his publicist and mention a tool I saw him post a couple of years ago.



This is obviously just a C-clamp with a blob brazed on one end, and a block of wood supporting the outside of the stay. Assuming the curvature of the block matches the curvature of the stay, this should pretty reliably indent the inside of the stay and only the inside.

On the other hand, I do really like using a really big hammer on my bikes now and then.

gugie 

I'm not worried about spreading the BB shell - framebuilding often requires a bit of bending down there.

I actually think Russel's method is quite elegant. Alignment check should always be done after any indentation.

52telecaster

My usual alignment check involves a ride but it would be better to use the string method.

bark_eater 

A big C clamp with 2 fitted wooden blocks placed out side of where the dimple is formed by the pipe would contain a lot of the spreading forces.

I do wonder if adding a vertical dimple to a chain stay that already has a horizontal crease would open the crease up and start a horizontal crack.

52telecaster

Good point. These stays had no crease or I wouldn't have needed to spread them. I only used this technique on frames that had undimpled oval stays. I'm only looking for 38-42 tire width. The 2" pipe gives me enough room to spare. It's not high art for sure but the frame that can't handle this stress probably can't handle me and camping gear on a long trip anyway.

Velo Mule

The problem with modern cameras, including or especially, cell phone cameras is that they are programed to autofocus on something in the frame. Often what you want to keep in focus and what the camera wants to focus on are different things. If @52telecaster wanted to take an artfully framed picture of his, are those 5-tens?, shoes, then, bingo, the camera focused on the right thing and the frame was artfully placed out of focus. Good job camera, except that Autoexposure is not talking to the autofocus so the subject of the picture, 52Telecasters shoe is too dark.

While modern camera have made great improvements in picture taking, they must be overridden sometimes to focus on what you want them to focus on. Then you still might have to post process the image to correct the auto exposure.

I ended up getting all techy, but just want to say, modern cameras still need a human.

Oh, and by the way, thanks for the tip on dimpling the chainstay. I may have to keep this in mind. I like the shape of the dimples for chainstays that have not been dimpled already. What are you doing for the brakes?

52telecaster

Tektro dual pivots. 800 series.

jdawginsc 

At least even if Russell’s solution splits the brazing on the chainstay bridge, the right and left dimples are sure to be perfectly aligned!

Interesting solutions found here...

bwilli88 

I have done the same thing to put 700c x 38mm on a Super Course.
Only I used a Barbell weight lock.

tiger1964 

Maybe not, some things sensitive eyes should not see?

I presume there's no specific tool made for this, perhaps there should be.

This looks like it takes courage; I just wonder what you'd be willing to do to, say, a 52 Telecaster...

nlerner

For my Lemond, I used a wood block, a steel rod, and my bench vise:





Before (right side):


After (right side)


Key to this process was that the chain stays were already kind of flattened, so the bit stayed in place while I squeezed the vice. I've tried it with more rounded stays and was unsuccessful.

Bad Lag

Regarding the pipe technique, how do you keep both dimples even (the same depth)? Does the direction of the hammering control which stay gets dented?



P.S. - try THAT with a graphite frame, sucka! :-)

52telecaster

Telecasters are tools that get grossly abused. For the record my 52 is a reissue but it's seen plenty of hard use. I have five teles and folks should send them to me if they want them reliced. Mine get dents almost every night I gig and that's 3-4 nights a week.

52telecaster

I think if my pipe were solid steel rod it would work better.

52telecaster

That looks good.

52telecaster

There is only room to hit the pipe in about one spot. I'm driving it between the stays. Since the stays are supposed to be the same thickness they dent fairly symmetrically. Straightening the frame after is recommended.

Bad Lag

This bit must be the key. An off-center, skewed blow would dent them unevenly.

How do you support the frame while striking the blows?

52telecaster

By the seat post in a bike stand. It really doesn't take huge amounts of effort.

due ruote 

At least with an iPhone, one can tap the screen pre-shutter to let the camera know what to focus on. Moreover, one can touch and drag up or down for more/less exposure. I can do this with my 6s. I assume later models have more tricks.
No idea about Android.